Control

The MCSimPython.control package contains a set of DP and Maneuvering controllers.

Basic Controllers

The module contains simple PD and PID controllers.

PD Controller

class MCSimPython.control.basic.PD(kp: list, kd: list)

Proportional-Derivative controller.

get_tau(eta, eta_d, nu, nu_d)

Calculate control loads.

Parameters:

  • eta (array_like) – Vessel pose in surge, sway and yaw.

  • eta_d (array_like) – Desired vessel pose in surge, sway and yaw (NED-frame).

  • nu (array_like) – Vessel velocity in surge, sway, and yaw (body-frame).

  • nu_d (array_like) – Desired vessel velocity in surge, sway and yaw (body-frame).

Returns:

tau – Controller load in surge, sway, and yaw (body-frame).

Return type:

array_like

set_kd(kd: list)

Set the derivative gain coefficients.

set_kp(kp: list)

Set the proportional gain coefficients.

PID Controller

class MCSimPython.control.basic.PID(kp: list, kd: list, ki: list, dt: float = 0.01)

Proportional-Derivative control with integral action.

get_tau(eta, eta_d, nu, nu_d)

Calculate control loads.

Parameters:

  • eta (array_like) – Vessel pose in surge, sway and yaw.

  • eta_d (array_like) – Desired vessel pose in surge, sway and yaw (NED-frame).

  • nu (array_like) – Vessel velocity in surge, sway, and yaw (body-frame).

  • nu_d (array_like) – Desired vessel velocity in surge, sway and yaw (body-frame).

Returns:

tau – Controller load in surge, sway, and yaw (body-frame).

Return type:

array_like

Backstepping Controllers

In the MCSimPython.control.backstepping module there are controllers based on backstepping theory. Currently, only a backstepping controller for maneuvering purposes has been implemented.

class MCSimPython.control.backstepping.BacksteppingController(M, D, K1, K2)

Backsteppipng controller for maneuvering.

The controller should be used together with a path parameterization guidance/reference model.

See also

MCSimPython.guidance.path_parm.WayPointPathParam

Way-points path parameterization.

control_law(z1, z2, alpha, alpha_dot, nu)

Complete control law.

error_pos(eta, eta_d)

Deviation from desired pose in body-frame.

error_vel(nu, alpha)

Deviation from virtual control law.

lyapunov_grad_s(z1, eta, eta_d_s)

Lyapunov function gradient.

u(eta, nu, eta_d, eta_d_s, eta_d_s2, mu, u_s, u_s_dot, ddt_u_s)

Control command.

unit_gradient_update_law(u_s, mu, eta_d_s, lyapunov_gradient)

Unit-tangent gradient update law for path parameter (s).

virtual_control_dot(z1, z2, alpha, eta, eta_d, eta_d_s, eta_d_s2, u_s, u_s_dot, nu, s_dot, ddt_u_s)

Time derivative of virtual control law (alpha_dot).

virtual_control_law(z1, eta, eta_d_s, u_s)

Virtual control law (alpha).